1. Field of the Invention
The present invention relates to valves and more particularly to a ball valve that combines the positive shut-off features of a ball valve and the control features of a needle and seat valve with an improved valve mechanism that has an erosion control trim.
2. Description of the Prior Art
U.S. Pat. No. 2,684,688, entitled Automatic Valve and System, issued to Homer G. Thornhill on July 27, 1954, teaches a valve that includes a valve body having a threaded inlet adapted to be connected to a side arm of a Christmas tree manifold. The valve body also has a flanged outlet adapted to be connected to a positive choke from which leads the pipe line going to the storage tank. The valve body is in the shape of a T, the inlet being at the base of the T, the other arm of the T projects a valve stem on which is mounted the valve which cooperates with a removable valve seat threadedly supported within the outlet. The valve stem is slideably supported within the center of the arm of the T opposite the outlet by means of a flanged valve bonnet. The valve bonnet is sealed to the end of the valve body by means of a ring gasket and is secured thereto by means of a fast coupling.
The valve bonnet is provided with two cylindrical bearings for supporting the cylindrical valve stem. Within each of the two annular grooves and within the bearings there is mounted a neoprene o-ring disposed between a pair of leather non-extrusion rings. These form a pair of spaced sliding seals between the valve stem and the valve bonnet.
U.S. Pat. No. 3,207,181, entitled Multiple Orifice Valve, issued to Robert S. Willis on Sept. 21, 1965, teaches a flow control valve which includes a valve body that has a longitudinally extended opening therein, an inlet leading to the opening and an outlet leading from the opening. The flow control valve also includes a pair of relatively rotatable disc carriers which are disposed within the opening. The flow control valve also includes a pair of relatively rotatable disc carriers which are disposed within the opening between the inlet and the outlet. Each disc carrier carries a disc so that the respective discs are in a contiguous relation to each other. The flow control valve further includes a device for rotating one of the disc carriers relative to the other disc carrier with the device therefor extending into the valve body. Each disc carrier is a body transversely spanning the opening and has an axially extended outer marginal skirt forming a seat for its disc. The discs and disc carriers have openings therethrough movable into and out of alignment to control the flow of fluid from the inlet to the outlet.
U.S. Pat. No. 3,426,797, entitled Multiple Orifice Valve, issued to William J. Baker on Feb. 11, 1969, teaches a fluid flow control valve having an axially aligned inlet and outlet with relatively rotatable flow controlling discs in face engagement containing respectively a pair of similarly positioned diametrically opposed orifices, a cylindrical disc carrier fixedly mounting one of the discs and having a central passage containing a separate sleeve liner connecting the disc orifice with the other disc and having an actuator handle which extends outwardly through an arcuate slot in the valve body, this carrier being sealed on opposite sides of the slot. The valve body is grooved between the seals and is provided with a drain port. The rotatable carrier has a central passage which connects its disc orifices with the inlet and is connected through the port passage with an annular chamber extending about the interface of the discs. The purpose of this fluid flow control valve is to provide a valve which may be installed in a flow line in such a manner that changes in the direction of flow through the valve are not necessary. This valve is adapted to be installed in an in-line conduit as distinguished from the flow control valve of U.S. Pat. No. 3,207,181 which is installed at an angular junction in the conduit. Neither the flow control valve of U.S. Pat. No. 3,207,181 nor the fluid flow control valve of U.S. Pat. No. 3,426,797 provides the positive shut-off capability of a ball valve. Furthermore, the orifices in the discs have a tendency to wear when the flow is reduced below twenty percent (20%) of an open valve.
U.S. Pat. No. 3,226,080, entitled Ball Valve Seat, issued to William E. Lowrey on Dec. 28, 1965, teaches a rotatable plug valve that includes a valve body that has a bore extending therethrough, a spherical valve member that is positioned in the bore and that has a port the axis of which is alignable with the axis of the bore in the open position of the valve end an aperture in the valve body. The rotatable plug valve also includes a stem that has an inner end which is engaged with the valve member and an axially outer end which extends through the aperture in the valve body and a device for forming a seal between the aperture and the stem. The rotatable plug valve further includes detachably connected end members which extend into each end of the bore in the valve body with each end member having a device which limits entry of the end member into the valve body a predetermined amount and with each end member also having a passage with which the port in the valve member can be aligned to form the run of the valve and an axially inner end having a portion taperingly diverging axially outward from the passage. The rotatable plug valve still further includes an annular groove in the taperingly diverging portion of the axial inner end with each annular groove having an inner and outer cylindrical walls which are disposed in coaxial relation with the respective passage and also having an end wall which is disposed in substantially normal relation with the cylindrical walls. There is also an annular seat member of deformable material which is positioned in each of the grooves with each seat member being of lesser radial thickness than the radial thickness of its groove so that in the uncompressed condition there is substantial clearance between the seat member and groove along the entire length of both the inner and outer circumferences of the groove. Each seat member has a portion which extends beyond the surface of the taperingly diverging portion terminating in a tapered surface to oppose the spherical surface of the valve member with each end member extending into the body bore an amount sufficient to force the seat member into intimate sealing contact with the spherical surface of the valve member upon assembly thereby deforming the seat member a limited amount so that the seat members do not completely fill the groove either during assembly or operation within rated pressure whereby the seat members act as a columnar spring against the spherical valve member.
Other ball valves are taught in U.S. Pat. No. 3,269,691, entitled Ball Valve Seal Support, issued to Robert J. Meima and James D. Aitken on Aug. 30, 1966, U.S. Pat. No. 3,269,692, entitled Ball Valve Construction, issued to Homer J. Shafer on Aug. 30, 1966, U.S. Pat. No. 3,269,693, entitled Ball Valve Seat, issued to Ronald A. Gullick on Aug. 30, 1966 and U.S. Pat. No. 3,357,679, entitled Multi-Material Elastomer Seal, issued to Robert A. Gullick on Dec. 12, 1967. The difficulty in using ball valves is that they do not regulate or control the fluid flow through the conduit. There is therefore a need for a ball valve that also has the capability of regulating and controlling fluid flow through the conduit. Such a ball valve should also have an axially aligned inlet and outlet so that it may be installed in an in-line conduit.
U.S. Pat. No. 3,880,399, entitled Multistage Noise Reducing Flow Control Valve, issued to Fred Joseph Luthe on Apr. 29, 1975, teaches a high pressure flow control valve that includes a valve cage which includes a plurality of pressure of reducing orifices.
U.S. Pat. No. 3,776,278, entitled Valve Including Noise Reducing Means, issued to Ernest E. Allen on Dec. 4, 1973, teaches a control valve which includes inlet and outlet ports, a valve seat and a cage member within which a valve plug is free to reciprocate toward and away from the valve seat to determine the flow therethrough. The cage member or valve plug are provided with a plurality of smoothwalled, narrow, substantially equally-spaced slots. In operation, the valve plug movement away from the valve seat controls fluid flow from the inlet port of the valve. The flow is directed through the slots, one dimension of which is sufficiently small to partition the flow, thereby to substantially attenuate the noise normally accompanying fluid flow through a control valve.